Because of their specific nature, siloxane compounds are very important compounds that are used in a variety of fields such as automotive industry, construction industry, electronics, and pharmaceuticals. In recent years, siloxane compounds have also become essential in the environmental and energy fields, for example, as sealing materials for LED and silane coupling agents for eco-tires, and it would not be an exaggeration to say that there is no field in which siloxane compounds are not used (market size as of 2009: 11.5 billion dollars, annual production volume: 1.23 million tons).
In general, the majority of siloxane compounds are synthesized via silanol compounds by hydrolysis, for example, by a sol-gel method using chlorosilane or an alkoxysilane as starting materials. Silanol compounds (inclusive of silane diols, silane triols, and silanetetraols), with the exception of some silane diols and silane triols having a bulky substituent group such as a phenyl group, are difficult to synthesize with a good yield because where water is present, condensation proceeds simultaneously with the hydrolysis. The silanol compounds are also known to have very low stability (stability in the presence of water) and condensate rapidly (NPL 2 and 3). For this reason, a large number of problems and limitations are associated with the silanol compounds, for example, (1) a large amount of reaction byproducts are formed; (2) the product structure is difficult to control; and (3) the silanol compounds cannot be adapted to reactions with substrates which are weak in water.
Accordingly, a method for synthesizing a silanol compound under anhydrous conditions or a method for synthesizing a siloxane compound not via a silanol compound are needed.
A method for treating silyl ether of pyrrolidine with n-BuLi to obtain a silanol compound is known as a method for synthesizing a silanol compound under anhydrous conditions (NPL 1). However, this method does not involve a reaction that is primarily aimed at the synthesis of a siloxane compound, and even when a siloxane compound is synthesized, the synthesis is difficult because the siloxane bonds are nucleophilically cleaved by n-BuLi.
Meanwhile, several methods based on cross coupling that uses a catalyst have been reported as methods for synthesizing a siloxane compound not via a silanol compound.
For example, Piers, Rubinsztajn, et al. have reported that siloxane bonds can be formed, while methane is being released, by reacting an alkoxysilane with hydrosilane in the presence of a B(C6F5)3 catalyst (NPL 4 and 5). However, the problem associated with this reaction is that an exchange reaction of substituent groups proceeds between the substrates of starting materials and the reaction cannot be controlled due to B(C6F5)3 which is a Lewis acid catalyst.
Bae et al. have recently reported that siloxane bonds can be formed, while methanole is being released, by reacting the following silanol compound and methoxysilane in the presence of a Ba(OH)2 catalyst (NPL 6). However, this reaction can be adapted to only very few stable silanol compounds, and the method is hardly suitable for industrial production.

Further, Kuroda et al. have reported that siloxane bonds can be formed, while an alkyl chloride is being released, by reacting the following alkoxysilane with chlorosilane in the presence of a bismuth chloride catalyst (NPL 7). However, this reaction is restricted to very few substrates, and the method is hardly suitable for industrial production.

Further, the problem associated with the methods disclosed in NPL 4 to 7 is that since all those methods use homogeneous catalysts, the catalysts are difficult to remove from the reaction system after the reaction and they remain in the product obtained.